Sensor applet update

This includes several changes:
- java applet uses async callback on initialization
- signed jar is used for test applet, because unsigned jars show warnings every time with latest java update
- applet remove is done in IE safe way
- a hack to handle one case of IE multi threading javascript. However it should be removed in favor if fixing the applet communication to prevent any multi threading.
- applet referencing is done in a more FF friendly way, however there still seems to be issues on FF
- there is now a lab.sensor-applet.js product that is used by the sensor experiements
- lab.sensor-applet.js supports multiple sensor collection
- this is using the a wip-revise-initialization branch of the sensor-applets repository, once this is merged to lab:master that should be changed back to sensor-applets:master
- there is a lenient force sensor definition so a user can select force and either force range will be accepted
- lab.sensor-applet.js supports specifying a parent element for the test applet, so its loading message, shows up within that element on the page.
- precision was added to to the definitions of the sensors, this isn't used by sensor model type but it is used by inquiry-space-importer experiment